阅读说明：本技术 一种基于核壳分层结构二氧化锡-氧化铜复合纳米材料的VOCs气体传感器的制备及应用 (Preparation and application of VOCs gas sensor based on core-shell layered structure tin dioxide-copper oxide composite nano material ) 是由 芦艳 马永华 于 2020-05-11 设计创作，主要内容包括：本发明公开了纳米功能材料、环境监测技术领域的一种基于核壳分层结构二氧化锡-氧化铜复合纳米材料的VOCs气体传感器的制备及应用,制备方法包括以下步骤：S1：Pd金属叉指电极的处理；S2：制备核壳分层结构二氧化锡-氧化铜复合纳米材料；S3：气敏材料的涂覆,将所述的VOCs气体传感器用于对不同浓度VOCs气体进行检测。制备方法简单,成本低廉,操作容易控制,具有较高的生产效率；缩小了传感器的体积；对VOCs气体具有灵敏度高,稳定性好检测速度快的特点。(The invention discloses a preparation method and application of a VOCs gas sensor based on a core-shell layered structure tin dioxide-copper oxide composite nanomaterial, belonging to the technical field of nano functional materials and environmental monitoring, wherein the preparation method comprises the following steps: s1: processing a Pd metal interdigital electrode; s2: preparing a core-shell layered structure tin dioxide-copper oxide composite nano material; s3: and coating a gas sensitive material, and using the VOCs gas sensor for detecting VOCs gases with different concentrations. The preparation method is simple, low in cost, easy to control in operation and high in production efficiency; the volume of the sensor is reduced; the method has the characteristics of high sensitivity, good stability and high detection speed for VOCs gas.)

1. A preparation method of a VOCs gas sensor based on a core-shell layered structure tin dioxide-copper oxide composite nano material is characterized by comprising the following steps:

s1: treatment of Pd metal interdigital electrode

Firstly, wiping Al with a pd metal interdigital electrode prepared by a screen printing technology by using acetone and ethanol cotton balls respectively₂O₃Cleaning the substrate, and adding Al₂O₃The substrate is sequentially placed in acetone, ethanol and deionized water, and is respectively cleaned by ultrasonic waves in the range of 5 toDrying for 10 minutes at the temperature of 100-120 ℃;

s2: preparation of core-shell layered structure stannic oxide-copper oxide composite nano material

S2.1: weighing copper acetylacetonate and stannic chloride according to a certain molar ratio, fully dissolving in methanol, and carrying out solvothermal reaction on the obtained mixed solution at a certain temperature;

s2.2: after the solvothermal reaction is finished, naturally cooling to room temperature, filtering and washing a product obtained by the reaction, and then putting the product into an oven for drying;

s2.3: after the drying, directly calcining the obtained product in a muffle furnace, and naturally cooling to obtain the core-shell layered structure tin dioxide-copper oxide composite nano material;

s3: coating of gas sensitive materials

Putting the dried tin dioxide-copper oxide composite nano material with the core-shell layered structure into a mortar, and grinding for 20-30 minutes; then, dripping deionized water into the mortar, and continuously grinding for 20-30 minutes to obtain viscous slurry; dipping a small amount of slurry by using a small hairbrush, coating the slurry on a Pd metal finger electrode, and drying the Pd metal finger electrode at the temperature of 60-80 ℃ to obtain a tin dioxide-copper oxide composite nano material gas-sensitive layer with a core-shell layered structure and a thickness of 2-4 mu m; and finally, aging the prepared device for 24-72 hours under direct current of 40-80 mA in an environment with the relative humidity of 40% RH and the temperature of 20-35 ℃ to obtain the VOCs gas sensor based on the core-shell layered structure tin dioxide-copper oxide composite nano material.

2. The preparation method of the VOCs gas sensor based on the core-shell layered structure tin dioxide-copper oxide composite nanomaterial according to claim 1, characterized by comprising the following steps: the preparation method of the Pd metal interdigital electrode comprises the following steps:

preparing a pd metal interdigital electrode by adopting a screen printing technology, and printing ink: pd powder: the mass ratio of the diluent is 1: 1: 2, stirring to prepare paste; and then injecting the paste onto a silk screen plate with the interdigital electrode pattern, scraping the paste under the conditions of an inclination angle of 30-45 degrees and a pressure of 5-10N, printing the electrodes, drying, and curing by ultraviolet light to complete the preparation of the metal interdigital electrode.

3. The preparation method of the VOCs gas sensor based on the core-shell layered structure tin dioxide-copper oxide composite nanomaterial according to claim 1, characterized by comprising the following steps: the ink type adopts Jiahua JX 07500487.

4. The preparation method of the VOCs gas sensor based on the core-shell layered structure tin dioxide-copper oxide composite nanomaterial according to claim 1, characterized by comprising the following steps: the width and the electrode spacing of the pd metal interdigital electrode are both 0.15-0.20 mm, and the thickness is 100-150 nm.

5. The preparation method of the VOCs gas sensor based on the core-shell layered structure tin dioxide-copper oxide composite nanomaterial according to claim 1, characterized by comprising the following steps: the solvothermal reaction temperature is 110-220 ℃, and the solvothermal reaction time is 6-48 hours.

6. The preparation method of the VOCs gas sensor based on the core-shell layered structure tin dioxide-copper oxide composite nanomaterial is characterized in that the molar ratio of copper acetylacetonate to tin tetrachloride is 1:1, and the molar concentration of the copper acetylacetonate is 0.01-0.1 mol/L.

7. The preparation method of the VOCs gas sensor based on the core-shell layered structure tin dioxide-copper oxide composite nanomaterial according to claim 1, characterized by comprising the following steps: the drying conditions of the oven are as follows: drying for 1-5 hours at the temperature of 60-120 ℃, wherein the temperature programming rate is 2-10 ℃/min.

8. The preparation method of the VOCs gas sensor based on the core-shell layered structure tin dioxide-copper oxide composite nanomaterial according to claim 1, characterized by comprising the following steps: the temperature rise rate of the temperature programming in the muffle furnace is in the range of 2-20 ℃/min, the calcination time is 2-8 hours, and the calcination temperature is 500-800 ℃.

9. The preparation method of the VOCs gas sensor based on the core-shell layered structure tin dioxide-copper oxide composite nanomaterial according to claim 1, characterized by comprising the following steps: the mass ratio of the nano microspheres to the deionized water is 5: 1 to 3.

10. The application of the VOCs gas sensor based on the core-shell layered structure tin dioxide-copper oxide composite nano material is characterized in that: the VOCs gas sensor based on the tin dioxide-copper oxide composite nanomaterial with the core-shell layered structure, which is prepared by the method according to any one of claims 1 to 9, is used for detecting VOCs gases with different concentrations.

Technical Field

The invention relates to the technical field of nano functional materials and environmental monitoring, in particular to preparation and application of a VOCs gas sensor based on a core-shell layered structure tin dioxide-copper oxide composite nano material.

Background

Air pollution, water pollution and soil pollution are three major pollutions threatening the normal life of human beings, and in recent years, along with the development of industry and the increase of population, the air pollution becomes more and more serious, especially the pollution of indoor VOCs, and in addition, the exceeding of the VOCs in the room of people for most of time seriously threatens the healthy life of common people. In the VOCs pollution, the content of formaldehyde exceeds the standard, and medical research shows that the formaldehyde concentration is higher than 0.1mg/m after long-term exposure³Ring ofIn the environment, the probability of the human body suffering from leukemia is increased. Therefore, it is an urgent and significant matter to realize accurate monitoring of the content of VOCs in the environment where life is generated.

The gas sensor directly adsorbs detection gas by using a sensitive material, so that the electrical property and the like of the material are changed, and the concentration of the gas is detected by detecting the change of an output signal of a sensitive element of a peripheral circuit. Since there are many materials used for gas sensing, oxide semiconductor sensitive materials are mainly used at present. Oxide semiconductor sensitive materials with different morphologies have great influence on the gas-sensitive performance, so that the gas-sensitive performance is often improved by synthesizing the sensitive materials with different morphologies. In addition to this, the structure of the sensitive material also has an effect on the gas-sensing properties.

Based on the above, the invention designs the preparation and application of the VOCs gas sensor based on the core-shell layered structure tin dioxide-copper oxide composite nano material, so as to solve the above mentioned problems.

Disclosure of Invention

The invention aims to provide preparation and application of a VOCs gas sensor based on a core-shell layered structure tin dioxide-copper oxide composite nano material, so as to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme: a preparation method of a VOCs gas sensor based on a core-shell layered structure tin dioxide-copper oxide composite nano material comprises the following steps:

s1: treatment of Pd metal interdigital electrode

Firstly, wiping Al with a pd metal interdigital electrode prepared by a screen printing technology by using acetone and ethanol cotton balls respectively₂O₃Cleaning the substrate, and adding Al₂O₃Sequentially placing the substrate in acetone, ethanol and deionized water, respectively ultrasonically cleaning for 5-10 minutes, and finally drying at 100-120 ℃;

s2: preparation of core-shell layered structure stannic oxide-copper oxide composite nano material

S2.1: copper acetylacetonate and tin tetrachloride are weighed according to a certain molar ratio, then are put into methanol for full dissolution, and the obtained mixed solution is subjected to solvothermal reaction at a certain temperature.

S2.2: and (4) after the solvothermal reaction is finished, naturally cooling to room temperature, filtering and washing a product obtained by the reaction, and then putting the product into an oven for drying.

S2.3: and after the drying, directly calcining the obtained product in a muffle furnace, and naturally cooling to obtain the core-shell layered structure tin dioxide-copper oxide composite nano material.

S3: coating of gas sensitive materials

Putting the dried tin dioxide-copper oxide composite nano material with the core-shell layered structure into a mortar, and grinding for 20-30 minutes; then, dripping deionized water into the mortar, and continuously grinding for 20-30 minutes to obtain viscous slurry; dipping a small amount of slurry by using a small hairbrush, coating the slurry on a Pd metal finger electrode, and drying the Pd metal finger electrode at the temperature of 60-80 ℃ to obtain a tin dioxide-copper oxide composite nano material gas-sensitive layer with a core-shell layered structure and a thickness of 2-4 mu m; and finally, aging the prepared device for 24-72 hours under direct current of 40-80 mA in an environment with the relative humidity of 40% RH and the temperature of 20-35 ℃ to obtain the VOCs gas sensor based on the core-shell layered structure tin dioxide-copper oxide composite nano material.

Preferably, the preparation method of the Pd metal interdigital electrode comprises the following steps:

preparing a pd metal interdigital electrode by adopting a screen printing technology, and printing ink: pd powder: the mass ratio of the diluent is 1: 1: 2, stirring to prepare paste; and then injecting the paste onto a silk screen plate with the interdigital electrode pattern, scraping the paste under the conditions of an inclination angle of 30-45 degrees and a pressure of 5-10N, printing the electrodes, drying, and curing by ultraviolet light to complete the preparation of the metal interdigital electrode.

Preferably, the ink model is Jiahua JX 07500487.

Preferably, the width and the electrode spacing of the pd metal interdigital electrode are both 0.15-0.20 mm, and the thickness is 100-150 nm.

Preferably, the solvothermal reaction temperature is 110-220 ℃, and the solvothermal reaction time is 6-48 hours.

Preferably, the molar ratio of the copper acetylacetonate to the tin tetrachloride is 1:1, and the molar concentration of the copper acetylacetonate is 0.01 to 0.1 mol/L.

Preferably, the oven drying conditions are as follows: drying for 1-5 hours at the temperature of 60-120 ℃, wherein the temperature programming rate is 2-10 ℃/min.

Preferably, the temperature rise rate of the temperature programming in the muffle furnace is in the range of 2-20 ℃/min, the calcination time is 2-8 hours, and the calcination temperature is 500-800 ℃.

Preferably, the mass ratio of the nano microspheres to the deionized water is 5: 1 to 3.

The application of the core-shell layered structure tin dioxide-copper oxide composite nanomaterial-based VOCs gas sensor is characterized in that the core-shell layered structure tin dioxide-copper oxide composite nanomaterial-based VOCs gas sensor prepared by the method according to any one of claims 1 to 9 is used for detecting VOCs gases with different concentrations.

Compared with the prior art, the invention has the beneficial effects that: the VOCs gas sensor of the core-shell layered structure tin dioxide-copper oxide composite nanomaterial prepared by the invention has the advantages of simple preparation method, low cost, easiness in operation control and higher production efficiency; the tin dioxide/copper oxide composite nanomaterial with the core-shell structure for the VOCs gas sensor enhances the catalytic conversion effect on VOCs gas, thereby improving the detection sensitivity on VOCs and reducing the volume of the sensor; the method has the characteristics of high sensitivity, good stability and high detection speed for VOCs gas.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a flow chart of the preparation method of the present invention;

FIG. 2 is a schematic diagram of the structure of a VOCs gas sensor made in accordance with the present invention;

FIG. 3 is a graph showing the sensitivity-VOCs concentration characteristics of the VOCs gas sensor of the present invention at a working temperature of 220 ℃;

FIG. 4 is a diagram showing the selective characteristics of the VOCs gas sensor of the present invention at a working temperature of 220 deg.C and a VOCs gas concentration of 100 ppm.

In the drawings, the components represented by the respective reference numerals are listed below:

1、Al₂O₃a substrate; 2. pd metal interdigital electrodes; 3. and (3) a composite nano material gas-sensitive layer.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.